What is CVE-2021-38165?

CVE-2021-38165 is a medium-severity vulnerability in Lynx Project, classified under Insufficiently Protected Credentials. CVSS score: 5.3/10. Published 2021-08-07.

How severe is CVE-2021-38165?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Is CVE-2021-38165 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Lynx Project

CVE-2021-38165

Lynx through 2.8.9 mishandles the userinfo subcomponent of a URI, which allows remote attackers to discover cleartext credentials because they may appear in SNI data.

Published 2021-08-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.041 (90.4th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 90.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.041 · newest: 0.041 · change: 0.000

Affected products

Lynx Project
Debian Linux — versions 9.0, 10.0
Fedoraproject Fedora — versions 33, 34, 35

Weakness classification (CWE)

CWE-522 — Insufficiently Protected Credentials

Public proof-of-concept exploits

References

bugs.debian.org/991971 (Third Party Advisory, Issue Tracking)
www.openwall.com/lists/oss-security/2021/08/07/1 (Mailing List, Third Party Advisory)
lynx.invisible-island.net/current/CHANGES.html (Third Party Advisory, Release Notes)
github.com/w3c/libwww/blob/f010b4cc58d32f34b162f0084fe093f7097a61f0/Library/src… (Third Party Advisory)
www.openwall.com/lists/oss-security/2021/08/07/9 (mailing-list, Mailing List, Third Party Advisory)
www.openwall.com/lists/oss-security/2021/08/07/11 (Mailing List)
www.openwall.com/lists/oss-security/2021/08/07/12 (mailing-list, Mailing List, Third Party Advisory)
www.openwall.com/lists/oss-security/2021/08/07/11 (mailing-list, Mailing List, Third Party Advisory)
lists.debian.org/debian-lts-announce/2021/08/msg00010.html (mailing-list, Mailing List, Third Party Advisory)
www.debian.org/security/2021/dsa-4953 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2021-38165?: CVE-2021-38165 is a medium-severity vulnerability in Lynx Project, classified under Insufficiently Protected Credentials. CVSS score: 5.3/10. Published 2021-08-07.
How severe is CVE-2021-38165?: Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2021-38165 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.